1. Field
The present invention generally relates to water supply systems for ballast water, cooling water, and auxiliary service water on marine vessels. More particularly, this invention relates to gathering or collecting water for water supply systems on marine vessels from a location away from the vessel to minimize environmental impact to an area where the marine vessel is operating.
2. Description of the Related Art
Marine vessels, such as cargo ships and cruise ships, have been used for years to transport cargo or people from port to port all over the world. The ports are typically located onshore near a body of water, and the ships are typically moored nearby to facilitate loading and unloading of the cargo or people. To provide for the operation of the vessel, there are provisions for the vessel to bring aboard water surrounding the vessel for the purposes of ballast, cooling, and other miscellaneous auxiliary services. Generally, water brought aboard a vessel falls into one of two categories, one being ballast water and the other being cooling or auxiliary service water.
Typically, the vessels are configured to displace a specific amount of water in order to maintain stability and/or provide maneuverability in the water, among other factors, and ballast water may facilitate this displacement. Ballast water may be water which is gathered and retained aboard the vessel until discharged at, or enroute to, a different location or port. To facilitate displacement of the vessel, the vessel typically includes one or more integral ballast tanks configured to receive and store the water, and to expel the water when desired. The water used to fill the ballast tanks is typically collected from the water around the vessel, and the ballast tanks may be filled or purged by an onboard system of pumps that is in communication with the ballast tanks on the vessel.
To provide for the operation of machinery and equipment on board the vessel, water is needed to perform a variety of duties. Cooling or auxiliary service water may be brought aboard for the purposes of cooling equipment or machinery, or performing some other required duty aboard the vessel, generally being discharged back into the surrounding water on completion of the duty. Typically, vessels will be provided propulsive and/or electrical power through diesel, steam, or gas turbine prime movers. In some cases, excess heat required to be removed from this equipment in the course of its operation is done through the transfer of heat to water that is taken from the surrounding area, put into the required service aboard the vessel, and thereupon returned by discharging the water back into the surrounding environment. In other cases, the water may be needed aboard the vessel to perform duties unrelated to power development. These activities may include providing sealing water for rotating equipment or other equipment, providing water for firefighting, supply water for reverse osmosis filtration or other types of distillation plants, and providing for sanitary water requirements, among other uses.
The water supplied for the purposes of use in ballast tanks, cooling water, and/or auxiliary services is typically collected by inlet conduits or intakes, sometimes referred to as sea chest openings, that are integral to the vessel hull and in communication with the ballast tanks or other systems for which the water is required. While these inlet conduits may include a grating or mesh to filter large debris during operation, the gratings typically do not exclude smaller debris and/or marine life, such as aquatic species of plants and animals. The introduction of certain marine life into the vessel's water intake system, for example fish species inadvertently pulled into the inlet conduit, may injure or kill the fish irrespective of the duty the water will perform aboard the vessel. Moreover, in the case of water brought aboard for ballast service, any marine biota, for example fish species and other organisms, surviving transfer into a ballast tank will be locationally displaced. This injury, unintentional eradication, or locational displacement of fish species may negatively impact the ecological balance in the body of water in which the vessel is docked, or the possibility of negative environmental impact to fish species may limit the docking or landing possibilities of the vessel. For example, estuaries, preserves, and other ecologically sensitive or protected marine areas may not be available as potential landing sites for the vessel. This limited docking potential may, in turn, prevent or minimize commercial ventures in certain areas, or may limit the availability of certain products in an area where the products may be used, thus forcing the products to be off-loaded at distant ports and transported to the area by alternate means.
As interest in ecologically sensitive areas grows, companies and other commercial interests desiring to create landing sites have become more cognizant of the fragile ecological balances in these areas. Some of these companies have made commitments to operating in these areas in a manner that not only maintains the ecological balance, but monitors and reacts to ecological shifts in these areas in an effort to enhance the ecosystem. Challenges exist for these companies as the typical vessel to be moored at the landing site may be an older vessel and/or is not equipped to limit impact to the area due to the age of the vessel, or the vessel is mechanically deficient of some apparatus that may limit environmental impact. For example, the companies that operate the landing sites often do not have a say in the age or manufacture of the vessel that is used to transport the cargo to the landing site. Thus, these companies have been challenged to make these vessels more ecologically friendly without major redesigns in the vessel itself.
Therefore, there is a need in the industry for a water intake filtering system that minimizes or eliminates intake of, and injury to, marine life and which also provides for retaining on board the vessel the water that is heated through cooling duty, both while maintaining an acceptable flow of water to support vessel requirements.